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Organisation Flashcards

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1
Q

Describe the digestive process

A

Food is chewed in the mouth. Enzymes in the saliva begin to digest starch into smaller sugar molecules.
The food passes down through the oesophagus into the stomach. In the stomach enzymes begin the digestion of proteins. The stomach also contains HCL which helps breaks down food and kills bacteria. The contraction of the muscles in the stomach breaks down food into a fluid. This passes into the small intestine where chemicals are released from the liver and the pancreas into the small intestine. The pancreas releases enzymes which continue the digestion of starch and protein and start the digestion of lipids. The liver releases bile to speed up the digestion of lipids. Food molecules are absorbed into the bloodstream. In the large intestine water is absorbed into the bloodstream. And the faeces is released from the body.

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2
Q

Define enzymes

A

Enzymes catalyze chemical reactions

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3
Q

Describe the lock and key theory

A

Enzymes bind to a substrate which has a complementary shape to its active site.
The substrate is specific to the enzyme
Enzyme breaks down substrate into smaller molecules

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4
Q

Enzymes in the digestive system

A

Protease breaks down proteins into amino acids.
Carbohydrase breaks down carbohydrates into simple sugars
Lipase breaks down lipids in fatty acids and glycerol.

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5
Q

What are factors that affect enzyme activity

A

pH
Temperature

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6
Q

How temperature affects enzyme activity

A

As the temperature increases the activity of the enzyme increases.
This is because as the temperature increases the enzyme and substrate move faster so there are more enzyme substrate collisions.
The enzyme works at the fastest possible rate at the optimum temperature.
As we increase the temperature past the optimum, then The activity of the enzyme rapidly decreases. This is because the shape of the active site is denatured.

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7
Q

How pH affects enzyme activity

A

The enzyme has an optimum pH where the activity is maximum
If we make the pH more acidic or more alkaline then the activity drops to zero because the active site denatures.
Each enzyme has a specific optimum pH

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8
Q

How the small intestine is adapted for absorption

A

The small intestine is very long providing a very large surface area for the absorption of molecules produced by digestion.
Villi increases the surface area for the absorption of molecules.
Villi have a very good blood supply so the bloodstream rapidly removes the products of digestion, increasing the concentration gradient.
Villi have a thin membrane which ensures a short diffusion path.

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9
Q

Describe the structure of the heart

A

Has 4 chambers: Left and right ventricles and atrium.
Vena cava brings in deoxygenated blood from the body into the right atrium.
The blood passes from the heart to the lungs through the pulmonary artery when the right ventricle contracts.
In the lungs the blood collects oxygen
Oxygenated blood passes from the lungs to the heart through pulmonary vein into the left atrium
Oxygenated blood is pumped from the heart to the body through the aorta from the left ventricle.

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10
Q

What do valves do

A

Prevent the back flow of blood

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11
Q

What is a pacemaker

A

Controls the natural resting heart rate

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12
Q

Where is a pacemaker found

A

In the right atrium

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13
Q

What’s an artificial pacemaker

A

A small electrical device that controls irregularities in the heart rate
It is implanted if the natural pacemaker stops working.

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14
Q

Describe the function and structure of arteries

A

Arteries carry very high pressure blood from the heart to the organs in the body.
Adaptations:
Very thick muscular walls allowing them to withstand the very high pressure of blood.
Contain elastic fibres which stretch when the surge of blood passes through and then recoil in between surges, which keeps the blood moving.

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15
Q

Describe the function and structure of capillaries

A

When the blood passes through capillaries substances such as glucose and oxygen diffuse from the blood to the cells. Carbon dioxide diffuse from the cells back to the blood.

Adaptations:
Have very thin walls so diffusion pathway is very short allowing substances to diffuse rapidly between the blood and body cells.

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16
Q

Describe the function and structure of veins

A

Blood makes its way back to the heart in veins.

Adaptations:
Veins have a thin wall as the blood pressure is low so the wall doesn’t need to be thick.
They contain valves to stop the blood flowing backwards.

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17
Q

What are the parts of the blood

A

Plasma
RBC
WBC
Platelets

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18
Q

Function of plasma

A

The liquid part of the blood which transports dissolved substances around the body.
Plasma transports:
Soluble digestion products from the small intestine to other organs.
Carbon dioxide from the organs to the lungs to be breathed out.
Urea from the liver to the kidneys to be excreted in urine.

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19
Q

Function of RBC and adaptations

A

RBC transports oxygen from the lungs to the body cells
Adaptations:
Contains haemoglobin
Have no nucleus so more room for haemoglobin
Has a biconcave disc shape for a larger surface area so oxygen diffuses in and out rapidly

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20
Q

Function of WBC and adaptations

A

Part of the immune system as they make antibodies.

Adaptations:
Contain a nucleus which contains DNA which encodes instructions that the wbc need to do their job.

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21
Q

Function of platelets

A

Platelets help the blood to clot.

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22
Q

Risks with blood donation

A

The body’s immune system will reject the blood and the patient can die if it’s of a different blood type.
Risk of infection

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23
Q

Describe CHD

A

In CHD layers of fatty material build up in the coronary arteries causing the coronary arteries to narrow.
This reduces the flow of blood to the coronary arteries.
This results in a lack of oxygen for the heart muscle.
In extreme cases this can result in a heart attack, where the heart is starved of oxygen.

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24
Q

Treatments for CHD

A

Statins:
Drugs which reduce the level of cholesterol in the blood. This slows down the rate that fatty materials build up in the arteries.

Stent:
A tube inserted into the coronary artery to keep it open.

25
Q

Evaluate statins as a treatment for CHD

A

Advantages:
Statins have been proven to reduce the risk of CHD.

Disadvantages:
Statins have some unwanted side effects for example liver problems.

26
Q

Evaluate stents as a treatment for CHD

A

Advantages:
Blood can flow normally through the artery

Disadvantages:
However, a stent will not prevent other regions of the coronary arteries from narrowing. It does not treat the underlying causes of the disease.

27
Q

How to treat leaky valves

A

Mechanical valves or valves from an animal

28
Q

Evaluate Mechanical valves

A

Mechanical valves last a lifetime but they increase the risk of blood clots so patients have to take anticlotting drugs for the rest of their life.

29
Q

Evaluate biological heart valves

A

Valves from animals do not last as long as mechanical valves and may need to be replaced.
However, patients don’t need to take anticlotting medications.

30
Q

What is heart failure

A

When the heart can’t pump enough blood around the body.

31
Q

Treatment for heart failure

A

Donated heart

32
Q

Problems with donated heart

A

There are not enough donated hearts available to treat every patient.
The patient must take drugs to stop the donated heart from being rejected by the body’s immune system.

33
Q

Problems with artificial hearts

A

Increase the risk of blood clotting.
They are not long-term solutions to heart failure.

34
Q

Describe the structure of the lung

A

Air passes into the lungs through the trachea
The trachea splits into two smaller tubes called bronchi, with one passing to each lung.
Further into the lungs, the bronchi subdivide into many smaller tubes called bronchioles.
The bronchioles end in tiny air sacs called alveoli

35
Q

What are alveoli

A

Alveoli are where gases diffuse in and out of the bloodstream

36
Q

How are alveoli adapted for gas exchange

A

There are many alveoli meaning the lungs have a huge surface area.
Alveoli have very thin walls so the diffusion path is very short.
The alveoli have a very good blood supply of capillaries ensuring the concentration gradient is steep.

37
Q

How is a tumor formed

A

Through uncontrolled cell division

38
Q

What’s a benign tumour

A

Benign tumors are growth of abnormal cells which are found in one area.
They are contained within a membrane.
Benign tumours do not invade other parts of the body. They stay in one place.

39
Q

What’s a malignant tumor

A

Malignant cells invade neighboring tissues and move into the bloodstream.
Malignant tumor cells are classed as a cancer
Once in the bloodstream, the malignant cells spread to different parts of the body and they form new tumors
Scientists call these new tumors secondary tumors

40
Q

What’s a communicable disease

A

Communicable diseases can be spread from person to person eg measles
Communicable diseases are spread by pathogens such as bacteria or viruses

41
Q

Define Non-communicable disease

A

Diseases that cannot be passed from person to person eg coronary heart disease

42
Q

Define health

A

The state of physical and mental wellbeing

43
Q

What is Epidemiology

A

Studying a disease to determine risk factors

44
Q

How to avoid bias when sampling

A

Take as large a sample as possible and it must be as random as possible

45
Q

Risk factors for cardiovascular diseases

A

A diet high in fat and low in vegetables increases the levels of certain types of cholesterol in the blood. This increases the rate that fatty materials build up in the arteries.

A diet high in salt can increase blood pressure, increasing the risk of developing cardiovascular diseases.

People who smoke also have an increased risk of developing cardiovascular disease

The risk is decreased in people who exercise regularly.

46
Q

Effects of smoking on unborn baby

A

Smoking when pregnant increases the risk of miscarriage and premature birth
It can also lead to the baby being born with a low body mass

Drinking alcohol when pregnant can cause fetal alcohol syndrome. Children born with fetal alcohol syndrome can have learning difficulties and other mental or physical problems.

47
Q

Effects of drinking alcohol on adults

A

Increased risk of liver cirrhosis and liver cancer.
Alcohol can also lead to addiction and memory loss.

48
Q

Function of the epidermis in a leaf

A

Protects the surface of the leaf.

49
Q

Adaptation of upper epidermis in a leaf

A

It’s transparent allowing light to pass through to the photosynthetic cells below.
It is covered with a thin layer of waxy cuticle

50
Q

What’s the purpose of the waxy cuticle

A

Reduces the evaporation of water from the surface of the leaf. This helps to prevent the leaf from drying out.

51
Q

Adaptation of the lower epidermis of the leaf

A

Has tiny pores called stomata

52
Q

What are stomata

A

Allow carbon dioxide to enter the leaf and oxygen to leave
Stomata also help to control the amount of water vapor that can pass out of the leaf

53
Q

Describe the palisade mesophyll

A

The palisade mesophyll consists of palisade cells which are packed with chloroplasts to absorb light for photosynthesis.

54
Q

What’s the spongy mesophyll

A

Air spaces in the spongy mesophyll allow CO2 to diffuse from the stomata through the spongy mesophyll to the palisade cells.
Oxygen also diffuses from the palisade cells through the spongy mesophyll to the stomata

55
Q

What is xylem tissue

A

Transports water from the roots to the stem and leaves
Some of the water is then used in photosynthesis
Xylem also transports dissolved minerals

56
Q

What’s phloem tissue

A

Transports dissolved sugars produced by photosynthesis from the leaves to the rest of the plant
This is called translocation

57
Q

Factors that affect rate of transpiration

A

The rate of transpiration is greater at higher temperatures because evaporation is faster when temperatures are high.

Transpiration is faster in dry conditions when it is not humid. This is because evaporation takes place more quickly under dry conditions

The rate of transpiration increases in windy conditions. This is because wind removes any water vapor, allowing more water to evaporate

The rate of transpiration increases when the light intensity increases as the rate of photosynthesis increases so stomata are now open to allow CO2 to enter.

58
Q

How does light intensity affect guard cells

A

When the light intensity is high the guard cells swell and they change their shape
This causes the stomata to open
Now CO2 can diffuse into the leaf and be used in photosynthesis.

Under hot conditions the plant closes its stomata to reduce water loss by transpiration. This ,sans that the plant cannot photosynthesise

Biology (10 decks)

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